Pivotal role of phosphodiesterase 10A in the integration of dopamine signals in mice striatal D-1 and D-2 medium-sized spiny neurones

Background and Purpose Dopamine in the striatum plays a crucial role in reward processes and action selection. Dopamine signals are transduced by D-1 and D-2 dopamine receptors which trigger mirror effects through the cAMP/PKA signalling cascade in D-1 and D-2 medium-sized spiny neurons (MSNs). Phosphodiesterases (PDEs), which determine the profile of cAMP signals, are highly expressed in MSNs, but their respective roles in dopamine signal integration remain poorly understood. Experimental Approach We used genetically encoded FRET biosensors to monitor at the single cell level the functional contribution of PDE2A, PDE4 and PDE10A in the changes of the cAMP/PKA response to transient and continuous dopamine in mouse striatal brain slices. Key Results We found that PDE2A, PDE4 and PDE10A operate on the moderate to high cAMP levels elicited by D-1 or A(2A) receptor stimulation. In contrast, only PDE10A is able to reduce cAMP down to baseline in both type of neurones, leading to the dephosphorylation of PKA substrates. Conclusion and Implications In both MSN types, PDE10A inhibition blunts the responsiveness to dopamine, whereas PDE2A or PDE4 inhibition reinforces dopamine action.